Manual wheelchairs are designed to be comfortable, lightweight, maneuverable and can be easily folded and stowed away. These salient features come at the cost of the occupant having to propel the wheelchair by manual force or rely on external help to push the wheelchair. It can be difficult for many wheelchair users to propel a manual wheelchair from one location to another. This is particularly true when traversing long distances or propelling a wheelchair over an obstacle. The manual effort required can sometimes lead to exhaustion or frequent breaks. Power wheelchairs on the other hand are very useful when covering long distances or when the occupant is unable to generate the forces required.
Most powered wheelchairs and powered scooters are heavy, complicated, expensive machines. They have small, fat tires and fairly complex joy stick-operated control systems. They generally include two electric motors that may be driven by one or more large lead-acid batteries. While intended for outdoor as well as indoor use, the machines are ill-suited for unpaved surfaces like grass and dirt. Nonetheless, powered wheelchairs and scooters have been a boon to the handicapped and elderly.
The present invention is specifically directed for application to standard manual wheelchairs. Despite the maneuverability and transportability of these manual wheelchairs, powered wheelchairs are far more capable of handling grades, soft surfaces such as grass and off road conditions. There are other devices for converting manual wheelchairs to power wheelchairs, but none provide a detachable electric drive unit having guide rails with a channel to support wheelchair wheels of the present invention. The present invention fulfills the need to enable light weight wheelchairs to be less expensively motorized and, if necessary, provide the option for remote control movement or other similar human interface devices for control without detracting from the appearance, maneuverability and transportability of the wheelchair.